Objectives. To determine if having done the voluntary military service is related to the sexual behavior of a population of young adults. Materials and methods. A cross-sectional study was carried out, which involved cadets enrolled in the Peruvian Air Force Sub Officer Academy of Peru, in 2010. For this study, civilians, as well as personnel who had performed voluntary military service, anonymously answered a self-administered questionnaire about their knowledge regarding HIV transmission and sexual risk behaviors. Results. 124 male participants took part in the study. 19.4% had performed voluntary military service and 80.6% were civilians. Those cadets who had performed voluntary military service knew more about HIV transmission than the civilians (p=0.04). Likewise, the former also had more occasional sexual partners in the last 12 months (p=0.04), number that doubled that of the civil personnel. Cadets with a record of voluntary military service informed to have consumed three times as much alcohol before their last sexual contact in comparison to the civilians (p=0.06). According to UNAIDS's definition, having performed voluntary military services was not a predictor of sexual risk behavior. Conclusions. Having performed voluntary military service was associated with having a better knowledge of HIV transmission. On the other hand, it seems to be related to having a higher number of occasional sexual partners. Finally, it was not found to be related to sexual risk behaviors.